1. Field of the Invention
The invention is related to an interactive touch system and a light source device thereof, and more particularly to an interactive touch display system and a light source device thereof.
2. Description of Related Art
An interactive projection system is a projection system for a user to perform touch operation on a projected area. The interactive projection system uses an invisible light beam (such as infrared light beam) emitted by a light source device to range over the projected area, so that the invisible light beam is reflected by a touch object (such as a finger of the user or a touch pen) when the user performs touch control on the projected area, so as to detect a touch position via the invisible light detecting device. So that the invisible light beam emitted by the light source device arranged at an edge of the projected area can range over the whole projected area, two light source devices adapted to emit invisible light beams having divergence angles equal to or larger than 90 degrees are generally combined into a light source device capable of emitting an invisible light beam having a divergence angle of at least 180 degrees. However, combining two light source devices increases the volume and cost and multiplies difficulty in assembly and adjustment.
Another way is to arrange a single light source device adapted to emit an invisible light beam having a divergence angle of 360 degrees at a center of an edge of the projected area, wherein the light source device includes a light-emitting element and a light-guide element, and the light-guide element has a conical surface. An invisible light beam emitted by the light-emitting element is reflected by the conical surface and then is able to generate an invisible light beam having a divergence angle of 360 degrees to range over the projected area. However, in this invisible light beam having the divergence angle of 360 degrees, only half of the invisible light beam (i.e. an invisible light beam having a divergence angle within a range of 180 degrees) proceeds toward the projected area and is used, and the other half of the invisible light beam (i.e. an invisible light beam within a range of another 180 degrees) does not proceed toward the projected area and thus becomes invalid light, resulting in low utilization efficiency of the invisible light beam emitted by the light source device.
U.S. patent number US20130135260 discloses an interactive device, wherein a lighting device thereof projects a light surface and forms an interactive surface, and a camera retrieves a picture frame that an object touches the interactive surface and thereby calculates a touched point position touched by the object on the interactive surface. Therein, the lighting device uses a conical reflective element to reflect light, so that the light diffuses in a circular fashion to form a fan-shaped light curtain. Chinese patent number CN202929344U discloses a laser light curtain system disposed at a central top position of a screen, emitting a laser light curtain that goes through a lens assembly and then is reflected by a conical mirror to generate a laser light curtain having a field angle larger than 180 degrees and parallel to the screen. Chinese patent number CN1479079A discloses a total reflection conical optical spreader within an optical lens, wherein a light beam emitted by a laser module has total reflection and becomes a light plane. Chinese patent number CN2791601Y discloses a conical reflex mirror, wherein a beam center of a laser beam overlaps an apex angle thereof, so that the laser beam becomes a horizontal laser light plane via reflection by the conical reflex mirror.